Re: [Phys-l] tuning forks

[Brian Whatcott <betwys1@sbcglobal.net>]

At 03:25 PM 3/8/2006, Dave Sykes, you wrote:
>  Why do tuning forks have two tines?
>
> (A student asked and I didn't have any answer)
>
> Dave

This feeds into an interesting digression
into the history of clocks.
Once upon a time, observatories used pendulum clocks.
 The pendulum could be temperature compensated, and
lightly loadedby a master/slave arrangement,
enclosing in a vacuum or
 temperature controlled enclosure.

But some seasonal and random variation remained.
It was found at length, that two pendulums swinging in
anti-phase, could be regulated more effectively, because
 much less motion was transferred to the pendulum's support.

 In the period immediately preceding
the crystal controlled wrist watch, which was embarrassingly
 superior to $1000 mechanical movements from say Rolex,
you will recall that Bulova introduced the electromagnetically
 excited tuning fork movement, which progressed to a silicon fork
 arrangement, thence to miniature crystals of the usual kind
 from the Far East which all but destroyed the Swiss market.

(Remember how Ampex developed the heli-scan VTR?
That business went East at a gallop, too.....)



Brian Whatcott    Altus OK    Eureka!